Medical research, especially research with pharmaceutical interventions, attempts to identify a dose-response relationship between the amount of a prescribed drug and the effect on an illness or disease. Identifying such a relationship facilitates the prescription of such medications in the proper and most effective doses. Paralleling this medical model, exercise scientists and fitness professionals are searching for a quantifiable relationship between dose (exercise) and response (specific health or fitness adaptations). For strength training, this dose-response relationship is vital to the prescription of proper doses of training. Over-prescription of resistance training exercise may result in over-stress injuries, whereas under-prescription will result in a failure to achieve the necessary or desired strength improvement. By optimizing the effort to benefit ratio (the amount and intensity of work to the degree of strength gain), exercise professionals can help their clients achieve the necessary or desired magnitude of strength gain in the most effective and efficient manner.
For strength development, a quantifiable relationship between the volume, intensity, and/or frequency of training and strength improvements has been somewhat elusive and controversial. Whereas much research has examined strength increases accompanying training interventions, most have examined only one or two training programs, providing only glimpses of a dose-response relationship. One of the most notable scientific studies was performed in the early 1960s (11). College-aged students were divided into nine groups, each being prescribed a different combination of sets and repetitions. Strength increases were analyzed between training programs, and it was concluded that three sets of six repetitions resulted in the greatest strength increases. This study demonstrated that different training volumes and intensities elicit different magnitudes of strength gains but only hinted toward a dose-response trend.
Of the various training variables, volume has received the most research attention. This attention has centered primarily on the debate concerning single-set training versus multiple-set programs. Numerous studies have compared such programs, and several narrative reviews (21,33) have summarized the results of these studies based on probability values, concluding that single-set programs elicit similar gains in strength as multiple sets. Unfortunately, much of this research has been performed with small sample sizes and consequently low statistical power (116). Methodological control may also have confused the issue as some past studies have failed to maintain stringent control of extraneous variables such as training intensity or periodization. In such situations, it may be difficult to identify accurate differences or trends in the data when relying solely on P values.
The American College of Sports Medicine (ACSM) recently issued a position stand after reviewing a large number of studies examining strength-training interventions (78). In this position stand, a follow-up and clarification of a previous statement (3), numerous issues including progression and variation of training, the application of training loads, and the differences in training prescription for trained and untrained populations were addressed. The statement concludes that as one progresses in training time and experience, the volume and intensity of training must be increased in order to continue to sufficiently stress the neuromuscular system. It did not, however, provide a quantifiable distinction between the magnitude of strength increases with specific volumes, intensities, or frequencies of training.
Fortunately, procedures exist that allow for a systematic and quantitative evaluation of strength-training research. The effect size (ES) proposed by Cohen (25) and the meta-analysis, popularized by Glass (44), provide for statistical evaluation of separate but related studies. The ES provides several benefits to researchers. First, it represents a standard unit for measuring and interpreting changes. Second, it allows for comparisons of different training methods within a single study. Finally, when used as part of a meta-analysis, the ES provides an acceptable method for combining and comparing the treatment effects of related studies.
Meta-analytical techniques provide a process by which treatment effects from various studies can be statistically combined and evaluated. The advantageous use of such techniques was recently illustrated in a meta-analysis of one-set versus three-set comparison studies (116). This analysis identified an added strength increase with three-set training by systematically and statistically evaluating the ES from 16 studies employing single- and triple-set comparison groups. This meta-analysis demonstrated that by combining the results of multiple studies and specifically analyzing the magnitude of the treatment effects, a greater understanding of the differences between the strength gains elicited by the different volumes was gained.
Unfortunately, a paucity of studies comparing one, two, three, four, or more sets of training limited the previous examination to a relatively few studies employing single- and triple-set comparison groups, providing limited information regarding the full dose-response relationship. This situation applies to research with frequency and intensity as well. However, the pre/post ES, representing a standardized mean difference (25), can also be computed in which an ES is calculated for a single treatment without comparison to a control group. With this procedure, past research examining strength-training programs can be combined, regardless of whether or not they included multiple comparison groups or a control group. This makes it possible to calculate an abundance of ES data from the existing strength-training literature to identify dose-response trends, a situation that may be impossible to accomplish in a single experimental design. The purpose of this investigation was to identify a quantitative dose-response relationship for strength development by calculating the magnitude of gains elicited by various levels of training intensity, frequency, and volume, thus clarifying the effort to benefit ratio.
Searches were performed for published and unpublished studies that included strength measurements before and after strength-training intervention programs. Computer searches of Science Citation Index, National Library of Medicine, Sport Discus, ERIC, and MEDLINE were performed. Hand searches of relevant journals and reference lists obtained from articles were conducted. Relevant studies were selected and searched for data necessary to compute ES and descriptive information regarding the training protocol.
Coding of studies.
Each study was read and coded by the primary investigator for the following variables: descriptive information including gender and age, frequency of training, mean training intensity, number of sets performed, and training status of the participants. Frequency was determined by the number of days per week that participants trained a particular muscle group. Intensity was coded as the average percent of one repetition maximum (1 RM) used throughout the training program. Volume was recorded as the number of sets performed (per muscle group) during each workout. Training status of the participants was divided into trained and untrained classifications. Participants must have been weight training for at least 1 yr before the study in order to be considered as trained.
Coder drift was assessed (104) by randomly selecting 10 studies for recoding. Per case agreement was determined by dividing the variables coded the same by the total number of variables. A mean agreement of 0.90 was required for acceptance.
Calculation and analysis of ES.
Pre/post ES were calculated with the following formula: [(Posttest mean − pretest mean)/pretest SD] (25). ES were then adjusted for sample size bias (55). This adjustment consists of applying a correction factor to adjust for a positive bias in smaller (N < 20) sample sizes (55). Descriptive statistics were calculated and univariate analysis of variance by groups was used to identify differences between training status, gender, and age with level of significance set at P ≤ 0.05.
The mean ES were calculated for both trained and untrained participants (Tables 1–3) and were found to differ significantly (F (2,1282)= −4.98, P < 0.05). ES for men and women were found to be similar (F (2,916)= 0.98, P > 0.05). Populations of 26- to 45-yr-olds experienced slightly larger treatment effects than other age groups (F (8,1424)= 7.44, P < 0.05); however, the dose-response curves were similar in shape for all ages. Training status was the only variable found to affect the dose-response curves. In untrained populations, 60% of 1 RM, 3 d·wk−1, employing four sets elicited the greatest magnitude of strength increases. In trained populations, 80% of 1 RM, training 2 d·wk−1, employing four sets per muscle group elicited maximal gains. Coder drift was calculated to be 0.91; thus, the coding process used in this study was found to be reliable.
This meta-analysis, the first of its kind to calculate the magnitude of strength increases with various levels of intensity, frequency, and volume, provides detailed information regarding the dose-response relationship for strength development. Analyzing the magnitude of strength gains in a large number of studies has resulted in quantitative information that researchers have struggled to pinpoint for many years. This information can help exercise professionals prescribe the appropriate dose of training programs designed to address the specific needs or goals of their clients.
An issue that should be considered when interpreting these data is the disparity between the numbers of ES calculated at certain levels of each variable. This disparity may result in a skewing of the dose-response trend at certain points. At least 10 ES were required for a specific level to be included in the analysis in hopes of avoiding such a skewing effect; however, the magnitude of the ES may change if the number of ES were equated. In spite of these disparities, these data have identified specific trends in the magnitude of strength increases at varying dosages of training. It should also be noted that only 21 studies involved subjects over the age of 55 yr, 13 studies included competitive athletes, and only six involved younger populations (<18 yr). Therefore, additional reviews are needed in order to verify the applicability of the dose-response trends to those populations.
Untrained individuals (those with less than 1 yr of consistent training) experience maximal gains with a mean training intensity of 60% of their 1 RM or approximately a 12 RM (Fig. 1). In trained individuals, a mean intensity of 80% of 1 RM or 8 RM elicits the greatest strength increase. This difference may be a result of the ability of a trained neuromuscular system to recover from and adapt to a higher intensity of training. It is also indicative of the need to increase the training load (progression) to sufficiently overload the neuromuscular system as one becomes more accustomed to training.
The trend in untrained populations becomes somewhat unstable with training intensities above 60% of 1 RM. This may be a result of differing numbers of available ES calculated in the studies reviewed; however, diminishing returns appears to begin in untrained individuals who train at higher intensities as the magnitude of strength improvements decreases as mean training intensity exceeds 60% of 1 RM. This drop occurs in trained populations who train above an average training intensity of 80% of 1 RM. Therefore, caution should be used when prescribing mean training intensities these levels for extended periods of time.
The ES for frequency of training also differed by training status (Fig. 2). Untrained individuals see a consistent dose-response as the number of days each muscle group is trained increases up to 3 d·wk−1. For trained individuals, 2 d·wk−1 (per muscle group) elicited the greatest strength increases. Programs in which each muscle group was trained 2 d·wk−1 at higher volumes were common among the training interventions for trained populations. This type of program results in more strenuous training and more recovery time between workouts. Such an approach may be too aggressive for untrained individuals who should perform three less strenuous workouts per week for maximal gains; however, additional research is needed to examine such training in untrained populations.
The effect size data calculated in the 140 studies reviewed clearly demonstrate that additional strength increases accompany training beyond single-set protocols (Fig. 3). In fact, both trained and untrained individuals experience the greatest gains (∼ twice the treatment effect of single sets) with a mean training volume of four sets per muscle group. These data support the previous meta-analysis (116), which determined that three-set programs elicit greater strength gains than single-set protocols and contradict the suggestions that single-set protocols elicit maximal or even similar strength gains as multiple sets (21,52). The additional contribution of this study to the scientific literature is the identification of the magnitude of strength increases with two, four, five, and six sets of training.
Previous authors (52) have concluded that in healthy, untrained adults, multiple-set training regimens provide little, if any, additional stimulus for improving adaptations during the initial training periods when compared with single-set protocols. They also suggest that single-set training regimens in recreationally trained individuals will continue to produce similar strength benefits as multiple-set programs. The magnitude of treatment effects from the 140 studies reviewed in this analysis fails to support either of these conclusions.
The magnitude of strength gain with multiple-set training in untrained populations identified here also contradicts the notion that untrained individuals are less sensitive to volume as compared with trained individuals (78). In fact, based on the differences in ES of one and four sets, untrained populations are more sensitive to increases in volume (+1.12) than trained populations (+0.7). This may relate to the greater potential for strength increases among untrained populations but demonstrates that they too follow a dose-response trend as volume is increased. However, caution should be used when prescribing high-volume training to untrained populations as adequate time is needed to become accustomed to the stress of resistance exercise and avoid over-stress injuries in the early phases of training. These individuals may also lack the desire to commit to a training program requiring the additional time needed to perform multiple sets and thus reduce adherence to the exercise regimen. These issues must be considered before prescribing multiple-set programs to those who have not been training consistently for at least 1 yr.
An examination of the ES for each set performed reveals that untrained individuals do experience a greater magnitude in strength gains at all volumes than do trained individuals. In fact, trained individuals must perform four sets to experience the same magnitude of strength gains as untrained individuals achieve with one set. This, again, is a result of an increased potential for strength improvements among those who are untrained or less trained as compared with those who have been training for an extended period of time and may be approaching a genetic limitation in overall strength development. It also represents the progression to higher volumes of training necessary as training experience increases.
It appears that diminishing returns begins in untrained individuals who perform more than four sets as the ES for five and six sets drop dramatically. For trained individuals, the mean ES for five sets is just slightly lower than four sets and insufficient ES were available for six sets. Therefore, the point at which this drop begins to occur in trained subjects is still speculative but may also occur with training above four sets. Caution should be used when prescribing strength-training programs of more than five or six sets until further data are available.
A note of particular importance regards the manner in which studies were coded for training volume. The number of sets performed per muscle group is a better indicator of the amount of training stress that a muscle experiences during a training session than sets per exercise. Programs professing to be single-set protocols may include multiple exercises stressing the same muscle group. This may result in a particular muscle group experiencing a stress similar to a multiple-set protocol for a single exercise. Previously overlooking such an issue may have confused the dose-response issue for volume by increasing the strength gains elicited by these single-set per exercise (but multiple set per muscle group) protocols.
Applications to exercise prescription.
A reoccurring theme in the current data relates to the importance of progression or progressive overload. Progression, with regard to strength training, is the gradual increase of stress placed upon the body during exercise (78). Such a principle is a vital characteristic in training programs of extended periods as the adaptive processes will only respond when faced with a stress to which they are not accustomed. As discussed in the ACSM’s position stand regarding progression models in resistance training (78), the initial standard of one set of 8–12 repetitions as suggested in previous position statements (3) was deemed appropriate for those individuals in the initial stages of training. However, that position statement did not include prescription guidelines for those individuals desiring continued gains in muscular fitness who must progress to higher volumes and intensities to avoid plateaus in adaptations. This analysis supports that conclusion.
Variation is also an important concept brought out by the current analysis as many of the studies included involved periodized training programs. Such programs did not involve the performance of solely four sets at 80% of 1 RM but incorporated varied training volumes and intensities (i.e., 3–5 sets at 70–90% of 1 RM). Therefore, the dose-response curves presented here represent mean training levels and should not be construed as supporting training at a particular volume or intensity on a constant basis. Rather, effective programs should incorporate varied training doses around the level of volume, frequency, and/or intensity corresponding to the degree of strength gain desired.
The issue of desired outcomes arises when applying the dose-response relationship to exercise prescription for strength gains. The desired magnitude of strength should be evaluated by the exercise professional and identified before attempting to prescribe a training program. It is apparent that lower levels of volume and intensity can result in improvements in strength. However, for maximal and continued adaptations over time, additional work at higher intensities must be performed. Exercise professionals should ascertain how much strength gain is needed or desired by their clients and then explain the effort-to-benefit ratio. This will enable them to make an informed decision regarding the amount of time and effort needed to achieve the desired/needed strength gains. For example, it would be unnecessary for an individual deemed to have adequate strength levels and simply desiring to maintain or slightly increase their current fitness to spend the time/effort needed to perform four sets at a high intensity. However, individuals seeking larger gains in strength will need to commit additional time and energy to their exercise sessions.
Resolution of the dose-response controversy among researchers, exercise and conditioning professionals, as well as the general public, is important as much confusion has resulted. The ACSM position statement on progression models (78) addressed this confusion, suggesting the necessity of progressive increases in volume, intensity, and frequency of training to facilitate the adaptive processes. The current study has presented additional evidence regarding the amount and intensity of work needed to elicit maximum gains. It also identifies the magnitude of strength gains with lower levels of training. Exercise prescription for strength increases is a complex process involving the manipulation of each of the variables discussed in this report. These dose-response curves should be consulted when designing resistance-training programs in order to prescribe the appropriate volume, intensity, and frequency to achieve the desired magnitude of strength increase.
References included in the analysis: (1, 2, 4–20, 22–24, 26–32, 34–43, 45–51, 53, 54, 56–77, 79–103, 105–115, 117–148).
1. Abernethy, P. J., and J. Jurimae. Cross-sectional and longitudinal uses of isoinertial, isometric, and isokinetic dynamometry. Med. Sci. Sports Exerc. 28: 1180–1187, 1996.
2. Adams, K. J., K. L. Barnard, A. M. Swank, E. Mann, M. R. Kushnick, and D. M. Denny. Combined high-intensity strength and aerobic training in diverse phase II cardiac rehabilitation patients. J. Cardiopulm. Rehabil. 19: 209–215, 1999.
3. American College of Sports Medicine. The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness
, and flexibility in healthy adults: position stand. Med. Sci. Sports Exerc. 30: 975–991, 1998.
4. Anderson, T., and J. T. Kearney. Effects of three resistance training programs on muscular strength and absolute and relative endurance. Res. Q. Exerc. Sport 53: 1–7, 1982.
5. Baker, D. The effects of an in-season of concurrent training on the maintenance of maximal strength and power in professional and college-aged rugby league football players. J. Strength Cond. Res. 15: 172–177, 2001.
6. Baker, D., G. Wilson, and R. Carlyon. Periodization: the effect on strength of manipulation volume and intensity. J. Strength Cond. Res. 8: 235–242, 1994.
7. Bamman, M. M., G. R. Hunter, B. R. Stevens, M. E. Guilliams, and M. C. Greenisen. Resistance exercise
prevents plantar flexor deconditioning during bed rest. Med. Sci. Sports Exerc. 29: 1462–1468, 1997.
8. Bell, G., D. Syrotuik, T. Socha, I. Maclean, and H. A. Quinney. Effect of strength training and concurrent strength and endurance training on strength, testosterone, and cortisol. J. Strength Cond. Res. 11: 57–64, 1997.
9. Bemben, D. A., N. L. Fetters, M. G. Bemben, N. Nabavi, and E. T. Koh. Musculoskeletal responses to high- and low-intensity resistance training in early postmenopausal women. Med. Sci. Sports Exerc. 32: 1949–1957, 2000.
10. Ben-Sira, D., A. Ayalon, and M. Tavi. The effect of different types of strength training on concentric strength in women. J. Strength Cond. Res. 9: 143–148, 1995.
11. Berger, R. Effect of varied weight training
programs on strength. Res. Q. 33: 168–181, 1962.
12. Berger, R. A. Comparative effects of three weight training
programs. Res. Q. 34: 396–398, 1963.
13. Bishop, D., D. G. Jenkins, L. T. Mackinnon, M. Mceniery, and M. F. Carey. The effects of strength training on endurance performance and muscle characteristics. Med. Sci. Sports Exerc. 31: 886–891, 1999.
14. Blakey, J. The combined effects of weight training
and plyometrics on dynamic leg strength and leg power. J. Appl. Sports Sci. Res. 1: 14–16, 1987.
15. Boyer, B. T. A comparison of the effects of three strength training programs on women. J. Appl. Sport Sci. Res. 4: 88–94, 1990.
16. Braith, R. W., J. E. Graves, S. H. Leggett, and M. L. Pollock. Effect of training on the relationship between maximal and submaximal strength. Med. Sci. Sports Exerc. 25: 132–138, 1993.
17. Braith, R. W., J. E. Graves, M. L. Pollock, S. L. Leggett, D. M. Carpenter, and A. B. Colvin. Comparison of 2 vs 3 days/week of variable resistance training during 10- and 18-week programs. Int. J. Sports Med. 10: 450–454, 1989.
18. Brandenburg, J. P., and D. Docherty. The effects of accentuated eccentric loading on strength, muscle hypertrophy, and neural adaptations in trained individuals. J. Strength Cond. Res. 16: 25–32, 2002.
19. Brown, A. B., N. Mccartney, and D. G. Sale. Positive adaptations to weight-lifting training in the elderly. J. Appl. Physiol. 69: 1725–1733, 1990.
20. Burke, D. G., S. Silver, L. E. Holt, T. Smith-Palmer, C. J. Culligan, and P. D. Chilibeck. The effect of continuous low dose creatine supplementation on force, power, and total work. Int. J. Sport Nutr. 10: 235–244, 2000.
21. Carpinelli, R. N., and R. M. Otto. Strength training: single versus multiple sets. Sports Med. 26: 73–84, 1998.
22. Chestnut, J. L., and D. Docherty. The effects of 4 and 10 repetition maximum weight-training protocols on neuromuscular adaptations in untrained men. J. Strength Cond. Res. 13: 353–359, 1999.
23. Chilibeck, P. D., A. W. Calder, D. G. Sale, and C. E. Webber. A comparison of strength and muscle mass increases during resistance training in young women. Eur. J. Appl. Physiol. Occup. Physiol. 77: 170–175, 1998.
24. Clutch, D., M. Wilton, C. Mcgown, and G. R. Bryce. The effect of depth jumps and weight training
on leg strength and vertical jump. Res. Q. Exerc. Sport 54: 5–10, 1983.
25. Cohen, J. Statistical Power Analysis for the Behavioral Sciences
, 2nd Ed. Hillsdale, NJ: Erlbaum, 1988, pp. xxi, 567.
26. Coleman, A. E. Comparison of weekly strength changes following isometric and isotonic training. J. Sports Med. Phys. Fitness 12: 26–29, 1972.
27. Coleman, A. E. Nautilus vs universal gym strength training in adult males. Am. Correct. Ther. J. 31: 103–107, 1977.
28. de Hoyos, D., T. Abe, L. Garzarella, C. J. Hass, M. Nordman, and M. L. Pollock. Effects of 6 months of high- or low-volume resistance training on muscular strength and endurance (Abstract). Med. Sci. Sports Exerc. 30: S165, 1998.
29. Evetovich, T. K., T. J. Housh, D. J. Housh, G. O. Johnson, D. B. Smith, and K. T. Ebersole. The effect of concentric isokinetic strength training of the quadriceps femoris on electromyography and muscle strength in the trained and untrained limb. J. Strength Cond. Res. 15: 439–445, 2001.
30. Ewing, J. L., Jr., D. R. Wolfe, M. A. Rogers, M. L. Amundson, and G. A. Stull. Effects of velocity of isokinetic training on strength, power, and quadriceps muscle fibre characteristics. Eur. J. Appl. Physiol. Occup. Physiol. 61: 159–162, 1990.
31. Faigenbaum, A. D., R. L. Loud, J. O’Connell, S. Glover, J. O’Connell, and W. L. Westcott. Effects of different resistance training protocols on upper-body strength and endurance development in children. J. Strength Cond. Res. 15: 459–465, 2001.
32. Fatouros, I. G., A. Z. Jamurtas, D. Leontsini, et al. Evaluation of plyometric exercise training, weight training
, and their combination on vertical jumping performance and leg strength. J. Strength Cond. Res. 14: 470–476, 2000.
33. Feigenbaum, M. S., and M. L. Pollock. Prescription of resistance training for health and disease. Med. Sci. Sports Exerc. 31: 38–45, 1999.
34. Fiatarone, M. A., E. C. Marks, N. D. Ryan, C. N. Meredith, L. A. Lipsitz, and W. J. Evans. High-intensity strength training in nonagenarians: effects on skeletal muscle. JAMA 263: 3029–3034, 1990.
35. Francaux, M., and J. R. Poortmans. Effects of training and creatine supplement on muscle strength and body mass. Eur. J. Appl. Physiol. Occup. Physiol. 80: 165–168, 1999.
36. Frontera, W. R., C. N. Meredith, K. P. O’Reilly, H. G. Knuttgen, and W. J. Evans. Strength conditioning in older men: skeletal muscle hypertrophy and improved function. J. Appl. Physiol. 64: 1038–1044, 1988.
37. Fry, A., D. Powell, and W. Kraemer. Validity of isokinetic and isometric testing modalities for assessing short-term resistance exercise
strength gains. J. Sports Rehabil. 1: 275–283, 1992.
38. Gallagher, P. M., J. A. Carrithers, M. P. Godard, K. E. Schulze, and S. W. Trappe. Beta-hydroxy-beta-methylbutyrate ingestion. Part I:. effects on strength and fat free mass. Med. Sci. Sports Exerc. 32: 2109–2115, 2000.
39. Garnica, R. Muscular power in young women after slow and fast isokinetic training. J. Orthop. Sport Phys. Ther. 8: 1–9, 1986.
40. Gettman, L. R., J. J. Ayres, M. L. Pollock, and A. Jackson. The effect of circuit weight training
on strength, cardiorespiratory function, and body composition of adult men. Med. Sci. Sports 10: 171–176, 1978.
41. Gettman, L. R., P. Ward, and R. D. Hagan. A comparison of combined running and weight training
with circuit weight training
. Med. Sci. Sports Exerc. 14: 229–234, 1982.
42. Gillam, G. Effects of frequency of weight training
on muscle strength enhancement. J. Sports Med. 21: 432–436, 1981.
43. Giorgi, A., G. J. Wilson, R. P. Weatherby, and A. J. Murphy. Functional isometric weight training
: its effects on the development of muscular function and the endocrine system over an 8-week training period. J. Strength Cond. Res. 12: 18–25, 1998.
44. Glass, G. V. Integrating findings: the meta-analysis of research. Rev. Res. Educ. 5: 351–379, 1977.
45. Godard, M. P., J. W. Wygand, R. N. Carpinelli, S. Catalano, and R. M. Otto. Effects of accentuated eccentric resistance training on concentric knee extensor strength. J. Strength Cond. Res. 12: 26–29, 1998.
46. Haennel, R. G., H. A. Quinney, and C. T. Kappagoda. Effects of hydraulic circuit training following coronary artery bypass surgery. Med. Sci. Sports Exerc. 23: 158–165, 1991.
47. Hakkinen, K., and P. V. Komi. Alterations of mechanical characteristics of human skeletal muscle during strength training. Eur. J. Appl. Physiol. Occup. Physiol. 50: 161–172, 1983.
48. Hakkinen, K., R. U. Newton, S. E. Gordon, et al. Changes in muscle morphology, electromyographic activity, and force production characteristics during progressive strength training in young and older men. J. Gerontol. A Biol. Sci. Med. Sci. 53: B415–B423, 1998.
49. Hakkinen, K., A. Pakarinen, W. J. Kraemer, R. U. Newton, and M. Alen. Basal concentrations and acute responses of serum hormones and strength development during heavy resistance training in middle-aged and elderly men and women. J. Gerontol. A Biol. Sci. Med. Sci. 55: B95–B105, 2000.
50. Harris, G. R., M. H. Stone, H. S. O’Bryant, C. M. Proulx, and R. L. Johnson. Short-term performance effects of high power, high force, or combined weight-training methods. J. Strength Cond. Res. 14: 14–20, 2000.
51. Harris, K. A., and R. G. Holly. Physiological response to circuit weight training
in borderline hypertensive subjects. Med. Sci. Sports Exerc. 19: 246–252, 1987.
52. Hass, C. J., M. S. Feigenbaum, and B. A. Franklin. Prescription of resistance training for healthy populations. Sports Med. 31: 953–964, 2001.
53. Hass, C. J., L. Garzarella, D. de Hoyos, and M. L. Pollock. Single versus multiple sets in long-term recreational weightlifters. Med. Sci. Sports Exerc. 32: 235–242, 2000.
54. Hasten, D. L., E. P. Rome, B. D. Franks, and M. Hegsted. Effects of chromium picolinate on beginning weight training
students. Int. J. Sport Nutr. 2: 343–350, 1992.
55. Hedges, L. V., and I. Olkin. Statistical Methods for Meta-Analysis
. Orlando, FL: Academic Press, 1985, pp. xxii, 369.
56. Herrick, A., and W. Stone. The effects of periodization versus progressive resistance exercise
on upper and lower body strength in women. J. Strength Cond. Res. 10: 72–76, 1996.
57. Hickson, R. C. Interference of strength development by simultaneously training for strength and endurance. Eur. J. Appl. Physiol. Occup. Physiol. 45: 255–263, 1980.
58. Hickson, R. C., B. A. Dvorak, E. M. Gorostiaga, T. T. Kurowski, and C. Foster. Potential for strength and endurance training to amplify endurance performance. J. Appl. Physiol. 65: 2285–2290, 1988.
59. Hickson, R. C., M. A. Rosenkoetter, and M. M. Brown. Strength training effects on aerobic power and short-term endurance. Med. Sci. Sports Exerc. 12: 336–339, 1980.
60. Hilyer, J. C., M. T. Weaver, J. N. Gibbs, G. R. Hunter, and W. V. Spruiell. In-station physical training for firefighters. Strength Cond. J. 21: 60–64, 1999.
61. Hisaeda, H., K. Miyagawa, S. Kuno, T. Fukunaga, and I. Muraoka. Influence of two different modes of resistance training in female subjects. Ergonomics 39: 842–852, 1996.
62. Hoff, J., J. Helgerud, and U. Wisloff. Maximal strength training improves work economy in trained female cross-country skiers. Med. Sci. Sports Exerc. 31: 870–877, 1999.
63. Hoffman, J. R., and S. Klafeld. The effect of resistance training on injury rate and performance in a self-defense instructors course for women. J. Strength Cond. Res. 12: 52–56, 1998.
64. Horvat, M., R. Croce, L. Poon, E. Mccarthy, and R. Keeney. Changes in peak torque and median frequency of the EMG subsequent to a progressive resistance exercise
program in older women. Clin. Kinesiol. 55: 37–43, 2001.
65. Hostler, D., M. T. Crill, F. C. Hagerman, and R. S. Staron. The effectiveness of 0.5-lb increments in progressive resistance exercise
. J. Strength Cond. Res. 15: 86–91, 2001.
66. Housh, D. J., T. J. Housh, J. P. Weir, L. L. Weir, P. E. Donlin, and W. K. Chu. Concentric isokinetic resistance training and quadriceps femoris cross-sectional area. Isokinetic Exerc. Sci. 6: 101–108, 1996.
67. Humphries, B., K. Mummery, R. U. Newton, and N. Humphries. Identifying bone mass and muscular changes. Adm. Radiol. J. 20: 7–11, 2001.
68. Humphries, B., R. U. Newton, R. Bronks, et al. Effect of exercise intensity on bone density, strength, and calcium turnover in older women. Med. Sci. Sports Exerc. 32: 1043–1050, 2000.
69. Hurley, B. F., R. A. Redmond, R. E. Pratley, M. S. Treuth, M. A. Rogers, and A. P. Goldberg. Effects of strength training on muscle hypertrophy and muscle cell disruption in older men. Int. J. Sports Med. 16: 378–384, 1995.
70. Jacobson, B. A comparison of two progressive weight training
techniques on knee extensor strength. Athl. Training
21:315–318, 390, 1986.
71. Jozsi, A. C., W. W. Campbell, L. Joseph, S. L. Davey, and W. J. Evans. Changes in power with resistance training in older and younger men and women. J. Gerontol. A Biol. Sci. Med. Sci. 54: M591–M596, 1999.
72. Kaminski, T. W., C. V. Wabbersen, and R. M. Murphy. Concentric versus enhanced eccentric hamstring strength training: Clinical implications. J. Athl. Training 33: 216–221, 1998.
73. Kaneko, M., R. F. Walters, and L. D. Carlson. Muscle training and blood flow. J. Sports Med. Phys. Fitness 10: 169–180, 1970.
74. Keeler, L. K., L. H. Finkelstein, W. Miller, and B. Fernhall. Early-phase adaptations of traditional-speed vs. superslow resistance training on strength and aerobic capacity in sedentary individuals. J. Strength Cond. Res. 15: 309–314, 2001.
75. Kelly, V. G., and D. G. Jenkins. Effect of oral creatine supplementation on near-maximal strength and repeated sets of high-intensity bench press exercise. J. Strength Cond. Res. 12: 109–115, 1998.
76. Kerr, D., A. Morton, I. Dick, and R. Prince. Exercise effects on bone mass in postmenopausal women are site-specific and load-dependent. J. Bone Miner. Res. 11: 218–225, 1996.
77. Kraemer, W. J. A series of studies: the physiological basis for strength training in American football: fact over philosophy. J. Strength Cond. Res. 11: 131–142, 1997.
78. Kraemer, W. J., K. Adams, E. Cafarelli, et al. American College of Sports Medicine position stand: progression models in resistance training for healthy adults. Med. Sci. Sports Exerc. 34: 364–380, 2002.
79. Kraemer, W. J., N. Ratamess, A. C. Fry, et al. Influence of resistance training volume and periodization on physiological and performance adaptations in collegiate women tennis players. Am. J. Sports Med. 28: 626–633, 2000.
80. Kraemer, W. J., J. S. Volek, K. L. Clark, et al. Influence of exercise training on physiological and performance changes with weight loss in men. Med. Sci. Sports Exerc. 31: 1320–1329, 1999.
81. Kramer, J., M. Stone, H. S. O’Bryant, et al. Effect of single vs. multiple sets of weight training
: impact of volume, intensity, and variation. J. Strength Cond. Res. 11: 143–147, 1997.
82. Larson-Meyer, D. E., G. R. Hunter, C. A. Trowbridge, et al. The effect of creatine supplementation on muscle strength and body composition during off-season training in female soccer players. J. Strength Cond. Res. 14: 434–442, 2000.
83. Larsson, L. Physical training effects on muscle morphology in sedentary males at different ages. Med. Sci. Sports Exerc. 14: 203–206, 1982.
84. Lemmer, J. T., D. E. Hurlbut, G. F. Martel, et al. Age and gender responses to strength training and detraining. Med. Sci. Sports Exerc. 32: 1505–1512, 2000.
85. Livolsi, J. M., G. M. Adams, and P. L. Laguna. The effect of chromium picolinate on muscular strength and body composition in women athletes. J. Strength Cond. Res. 15: 161–166, 2001.
86. Macdougall, J. D., G. R. Ward, D. G. Sale, and J. R. Sutton. Biochemical adaptation of human skeletal muscle to heavy resistance training and immobilization. J. Appl. Physiol. 43: 700–703, 1977.
87. Mazzetti, S. A., W. J. Kraemer, J. S. Volek, et al. The influence of direct supervision of resistance training on strength performance. Med. Sci. Sports Exerc. 32: 1175–1184, 2000.
88. Mccall, G. E., W. C. Byrnes, A. Dickinson, P. M. Pattany, and S. J. Fleck. Muscle fiber hypertrophy, hyperplasia, and capillary density in college men after resistance training. J. Appl. Physiol. 81: 2004–2012, 1996.
89. Mccarthy, J. P., J. C. Agre, B. K. Graf, M. A. Pozniak, and A. C. Vailas. Compatibility of adaptive responses with combining strength and endurance training. Med. Sci. Sports Exerc. 27: 429–436, 1995.
90. Mckethan, J. F., and J. L. Mayhew. Effects of isometrics, isotonics, and combined isometrics-isotonics on quadriceps strength and vertical jump. J. Sports Med. Phys. Fitness 14: 224–229, 1974.
91. Mclester, J. R., P. Bishop, and M. E. Guilliams. Comparison of 1 day and 3 days per week of equal-volume resistance training in experienced subjects. J. Strength Cond. Res. 14: 273–281, 2000.
92. Menkes, A., S. Mazel, R. A. Redmond, et al. Strength training increases regional bone mineral density and bone remodeling in middle-aged and older men. J. Appl. Physiol. 74: 2478–2484, 1993.
93. Meredith, C. N., W. R. Frontera, K. P. O’Reilly, and W. J. Evans. Body composition in elderly men: effect of dietary modification during strength training. J. Am. Geriatr. Soc. 40: 155–162, 1992.
94. Messier, S., and M. Dill. Alterations in strength and maximal oxygen uptake consequent to Nautilus circuit weight training
. Res. Q. Exerc. Sport 56: 345–351, 1985.
95. Miller, J. P., R. E. Pratley, A. P. Goldberg, et al. Strength training increases insulin action in healthy 50- to 65-yr-old men. J. Appl. Physiol. 77: 1122–1127, 1994.
96. Morriss, C. J., K. Tolfrey, and R. J. Coppack. Effects of short-term isokinetic training on standing long-jump performance in untrained men. J. Strength Cond. Res. 15: 498–502, 2001.
97. Nelson, M. E., M. A. Fiatarone, C. M. Morganti, I. Trice, R. A. Greenberg, and W. J. Evans. Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures: a randomized controlled trial. JAMA 272: 1909–1914, 1994.
98. Nichols, J. F., D. K. Omizo, K. K. Peterson, and K. P. Nelson. Efficacy of heavy-resistance training for active women over sixty: muscular strength, body composition, and program adherence. J. Am. Geriatr. Soc. 41: 205–210, 1993.
99. Nicklas, B. J., A. J. Ryan, M. M. Treuth, et al. Testosterone, growth hormone and IGF-I responses to acute and chronic resistive exercise in men aged 55–70 years. Int. J. Sports Med. 16: 445–450, 1995.
100. Nobbs, L., and E. Rhodes. The effect of electrical stimulation and isokinetic exercise on muscular power of the quadriceps femoris. J. Orthop. Sport Phys. Ther. 8: 260–268, 1986.
101. Noonan, D., K. Berg, R. W. Latin, J. C. Wagner, and K. Reimers. Effects of varying dosages of oral creatine relative to fat free body mass on strength and body composition. J. Strength Cond. Res. 12: 104–108, 1998.
102. Ohagan, F. T., D. G. Sale, J. D. Macdougall, and S. H. Garner. Comparative effectiveness of accommodating and weight resistance training modes. Med. Sci. Sports Exerc. 27: 1210–1219, 1995.
103. Ohagan, F. T., D. G. Sale, J. D. Macdougall, and S. H. Garner. Response to resistance training in young-women and men. Int. J. Sports Med. 16: 314–321, 1995.
104. Orwin, R. In: The Handbook of Research Synthesis, H. Cooper and L. V. Hedges (Eds.). New York: Russell Sage Foundation, 1994, pp. 139–162.
105. Ostrowski, K. J., G. J. Wilson, R. Weatherby, P. W. Murphy, and A. D. Lyttle. The effect of weight training
volume on hormonal output and muscular size and function. J. Strength Cond. Res. 11: 148–154, 1997.
106. Pearson, D. R., D. G. Hamby, W. Russel, and T. Harris. Long-term effects of creatine monohydrate on strength and power. J. Strength Cond. Res. 13: 187–192, 1999.
107. Peeters, B. M., C. D. Lantz, and J. L. Mayhew. Effect of oral creatine monohydrate and creatine phosphate supplementation on maximal strength indices, body composition, and blood pressure. J. Strength Cond. Res. 13: 3–9, 1999.
108. Pels, A. E., III, M. L. Pollock, T. E. Dohmeier, K. A. Lemberger, and B. F. Oehrlein. Effects of leg press training on cycling, leg press, and running peak cardiorespiratory measures. Med. Sci. Sports Exerc. 19: 66–70, 1987.
109. Perrin, D., S. Lephart, and A. Weltman. Specificity of training on computer obtained isokinetic measures. J. Orthop. Sports Phys. Ther. 17: 495–498, 1989.
110. Petersen, S., J. Wessel, K. Bagnall, H. Wilkins, A. Quinney, and H. Wenger. Influence of concentric resistance training on concentric and eccentric strength. Arch. Phys. Med. Rehabil. 71: 101–105, 1990.
111. Pollock, M. L., J. E. Graves, M. M. Bamman, et al. Frequency and volume of resistance training: effect on cervical extension strength. Arch. Phys. Med. Rehabil. 74: 1080–1086, 1993.
112. Pyka, G., E. Lindenberger, S. Charette, and R. Marcus. Muscle strength and fiber adaptations to a year-long resistance training program in elderly men and women. J. Gerontol. 49: M22–M27, 1994.
113. Reaburn, P., P. Logan, and L. Mackinnon. Serum testosterone response to high-intensity resistance training in male veteran sprint runners. J. Strength Cond. Res. 11: 256–260, 1997.
114. Reid, C. M., R. A. Yeater, and I. H. Ullrich. Weight training
and strength, cardiorespiratory functioning and body composition of men. Br. J. Sports Med. 21: 40–44, 1987.
115. Reynolds, T. H., P. A. Frye, and G. A. Sforzo. Resistance training and the blood lactate response to resistance exercise
in women. J. Strength Cond. Res. 11: 77–81, 1997.
116. Rhea, M. R., B. A. Alvar, and L. N. Burkett. Single versus multiple sets for strength: a meta-analysis to address the controversy. Res. Q. Exerc. Sport 73: 485–488, 2002.
117. Rice, C. L., D. A. Cunningham, D. H. Paterson, and J. R. Dickinson. Strength training alters contractile properties of the triceps brachii in men aged 65–78 years. Eur. J. Appl. Physiol. Occup. Physiol. 66: 275–280, 1993.
118. Rooney, K. J., R. D. Herbert, and R. J. Balnave. Fatigue contributes to the strength training stimulus. Med. Sci. Sports Exerc. 26: 1160–1164, 1994.
119. Ryan, A. S., M. S. Treuth, G. R. Hunter, and D. Elahi. Resistive training maintains bone mineral density in postmenopausal women. Calcif. Tissue Int. 62: 295–299, 1998.
120. Ryan, A. S., M. S. Treuth, M. A. Rubin, et al. Effects of strength training on bone mineral density: hormonal and bone turnover relationships. J. Appl. Physiol. 77: 1678–1684, 1994.
121. Sale, D. G., I. Jacobs, J. D. Macdougall, and S. Garner. Comparison of two regimens of concurrent strength and endurance training. Med. Sci. Sports Exerc. 22: 348–356, 1990.
122. Sanborn, K., R. Boros, R. Hruby, et al. Short-term performance effects of weight training
with multiple sets not to failure vs. a single set to failure in women. J. Strength Cond. Res. 14: 328–331, 2000.
123. Schlicht, J., D. N. Camaione, and S. V. Owen. Effect of intense strength training on standing balance, walking speed, and sit-to-stand performance in older adults. J. Gerontol. A Biol. Sci. Med. Sci. 56: M281–M286, 2001.
124. Schlumberger, A., J. Stec, and D. Schmidtbleicher. Single- vs. multiple-set strength training in women. J. Strength Cond. Res. 15: 284–289, 2001.
125. Schoitz, M., J. A. Potteiger, P. G. Huntsinger, and D. C. Denmark. The short-term effects of periodized and constant-intensity training on body composition, strength, and performance. J. Strength Cond. Res. 12: 173–178, 1998.
126. Siegel, J., D. Camaione, and T. Manfredi. The effects of upper body resistance training on prepubescent children. Pediatr. Exerc. 1: 145–154, 1989.
127. Smith, D. Effects of resistance training on isokinetic and volleyball performance measures. J. Appl. Sports Sci. Res. 1: 42–44, 1987.
128. Stamford, B. A., and R. Moffatt. Anabolic steroid: effectiveness as an ergogenic aid to experienced weight trainers. J. Sports Med. Phys. Fitness 14: 191–197, 1974.
129. Stanforth, P. R., T. L. Painter, and J. H. Wilmore. Alternation in concentric strength consequent to powercise and universal gym circuit training. J. Appl. Sport Sci. Res. 6: 152–157, 1992.
130. Starkey, D. B., M. L. Pollock, Y. Ishida, et al. Effect of resistance training volume on strength and muscle thickness. Med. Sci. Sports Exerc. 28: 1311–1320, 1996.
131. Staron, R. S., M. J. Leonardi, D. L. Karapondo, et al. Strength and skeletal muscle adaptations in heavy-resistance-trained women after detraining and retraining. J. Appl. Physiol. 70: 631–640, 1991.
132. Stiene, H. A., T. Brosky, M. F. Reinking, H. Nyland, and M. B. Mason. A comparison of closed kinetic chain and isokinetic joint isolation exercise in patients with patellofemoral dysfunction. J. Orthop. Sports Phys. Ther. 24: 136–141, 1996.
133. Stone, M. H., J. A. Potteiger, K. C. Pierce, et al. Comparison of the effects of three different weight-training programs on the one repetition maximum squat. J. Strength Cond. Res. 14: 332–337, 2000.
134. Stone, W. J., and S. P. Coulter. Strength/endurance effects from three resistance training protocols with women. J. Strength Cond. Res. 8: 231–234, 1994.
135. Stopka, C., L. Limper, R. Siders, J. E. Graves, and A. Goodman. Effects of a supervised resistance training program on adolescents and young adults with mental retardation. J. Strength Cond. Res. 8: 184–187, 1994.
136. Thomis, M. A. I., G. P. Beunen, H. H. Maes, et al. Strength training: importance of genetic factors. Med. Sci. Sport Exerc. 30: 724–731, 1998.
137. Tollback, A., S. Eriksson, A. Wredenberg, et al. Effects of high resistance training in patients with myotonic dystrophy. Scand. J. Rehabil Med. 31: 9–16, 1999.
138. Tomberlin, J., J. Basford, E. Schwen, P. Orte, S. Scott, R. Laughman, and D. Ilstrup. Comparative study of isokinetic eccentric and concentric quadriceps training. J. Orthop. Sports Phys. Ther. 14: 31–36, 1991.
139. Treuth, M. S., A. S. Ryan, R. E. Pratley, et al. Effects of strength training on total and regional body composition in older men. J. Appl. Physiol. 77: 614–620, 1994.
140. Venable, M. P., M. A. Collins, H. S. O’Bryant, C. R. Denegar, M. J. Sedivec, and G. Alon. Effect of supplemental electric stimulation on the development of strength, vertical jump, performance and power. J. Appl. Sport Sci. Res. 5: 139–143, 1991.
141. Volek, J. S., N. D. Duncan, S. A. Mazzetti, et al. Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training. Med. Sci. Sports Exerc. 31: 1147–1156, 1999.
142. Weir, J. P., D. J. Housh, T. J. Housh, and L. L. Weir. The effect of unilateral eccentric weight training
and detraining on joint angle specificity, cross-training, and the bilateral deficit. J. Orthop. Sports Phys. Ther. 22: 207–215, 1995.
143. Weir, J. P., T. J. Housh, and G. O. Johnson. The effect of dynamic constant external resistance training on the isokinetic torque-velocity curve. Int. J. Sports Med. 14: 124–128, 1993.
144. Weltman, A., C. Janney, C. B. Rians, et al. The effects of hydraulic resistance strength training in pre-pubertal males. Med. Sci. Sports Exerc. 18: 629–638, 1986.
145. Wenzel, R., and E. Perfetto. The effect of speed versus non-speed training in power development. J. Appl. Sports Sci. Res. 6: 82–87, 1992.
146. Willoughby, D. S., and S. Simpson. The effects of combined electromyostimulation and dynamic muscular contractions on the strength of college basketball players. J. Strength Cond. Res. 10: 40–44, 1996.
147. Young, W., and G. Bilby. The effect of voluntary effort to influence speed of contraction on strength, muscular power, and hypertrophy development. J. Strength Cond. Res. 7: 172–178, 1993.
148. Zmierski, T., S. Kegerreis, and J. Scarpaci. Scapular muscle strengthening. J. Sport Rehabil.. 4: 244–252, 1995.